Conventionally, a coreless wiring board is known. In the coreless wiring board, for example, an insulating layer and a wiring layer are alternately stacked, electrodes to be connected to a semiconductor chip are exposed at one side, and pads for external connection that are selectively exposed from a solder resist layer are formed at another side. The pads for external connection are connected to a mounting substrate such as a mother board by solder, for example (see Patent Document 1, for example).
As the coreless wiring board does not include a core, its rigidity is not sufficient and large warping may be generated in the wiring board. If warping is generated in the wiring board, there is a problem that it is difficult to connect the pads for external connection to the mounting substrate by the solder due to positional shifts between the pads for external connection and the mounting substrate.